Easy to use, with a lot of possibilities

This plugin comes as a godsend, more than 12 months ago, I searched and searched something similar, but I have not found anything functional. Till this morning.
On my installation of wordpress IT (3.6) I don’t have any problem, the interface is intuitive and simply-to-use

What I’d like to have as an additional feature? The possibility for admin to add a customized language. For example, a non-official language, a regional dialect … Obviously adding the flag and the necessary files.